A code-division multiple access base station assisted quality soft handoff algorithm screens or filters out candidate pilot signals from a pilot strength measurement message generated by a mobile station and provides the revised pilot strength measurement message to the mobile switching center of the mobile communication system. The mobile switching center subsequently conducts handoff processing in accordance with the revised pilot strength measurement message. If the combined pilot signal strength of the existing mobile station active legs is less than a first threshold, the current pilot strength measurement message is maintained. If the combined pilot signal strength of the existing mobile station active legs is greater than or equal to the first threshold, all candidate pilot signals are deleted from the pilot strength measurement message such that only pilot signals of existing mobile station active legs remain. Also, if the pilot signal strength of a candidate pilot signal is greater than a second threshold, the candidate pilot signal is added to the pilot strength measurement message. The number of handoffs per call are reduced using the revised pilot strength measurement message such that forward link power and network processing resources are conserved.
Legal claims defining the scope of protection, as filed with the USPTO.
1. A method of screening pilot signals of a pilot strength measurement message generated by a mobile station, the pilot strength measurement message identifying a pilot signal and pilot signal strength of at least one active leg of the mobile station and identifying at least one candidate pilot signal and pilot signal strength of the at least one candidate pilot signal, comprising the steps of: a) determining the combined pilot signal strength of the pilot signals of the active legs; b) comparing the combined pilot signal strength determined in said step a) to a first threshold; and c) providing a revised pilot strength measurement message which does not include the candidate pilot signals upon determination in said step b) that the combined pilot signal strength is greater than the first threshold.
2. The method of screening pilot signals of claim 1 , further comprising the steps of: d) comparing the pilot signal strength of a candidate pilot signal to a second threshold; and e) providing a revised pilot strength measurement message including the candidate pilot signal upon determination in said step d) that the pilot signal strength of the candidate pilot signal is greater than the second threshold.
3. The method of screening pilot signals of claim 2 , further comprising the steps of: f) comparing the pilot signal strength of a candidate pilot signal to the pilot signal strength of a strongest pilot signal of the active legs; and g) providing a revised pilot strength measurement message including the candidate pilot signal upon determination in said step f) that the pilot signal strength of the candidate pilot signal is greater than the pilot signal strength of the strongest pilot signal of the active legs.
4. The method of screening pilot signals of claim 1 , further comprising the step of: d) providing a revised pilot strength measurement message including the candidate pilot signals upon determination in said step b) that the combined pilot signal strength is less than the first threshold.
5. The method of screening pilot signals of claim 1 , wherein the pilot strength measurement message is transmitted from the mobile station to a base station and provided from the base station to a mobile switching center and screening of the pilot strength measurement message is carried out at the mobile switching center.
6. The method of screening pilot signals of claim 1 , wherein the active legs of the mobile station are code division multiple access legs.
7. The method of screening pilot signals of claim 1 , wherein the pilot strength measurement message is transmitted from the mobile station to a base station and screening of the pilot strength measurement message is carried out at the base station.
8. A base station of a mobile communication system, the base station receiving a pilot strength measurement message generated by a mobile station, the pilot strength measurement message identifying a pilot signal and pilot signal strength of at least one active leg of the mobile station and identifying at least one candidate pilot signal and pilot signal strength of the at least one candidate pilot signal, the base station comprising: a controller that revises the pilot strength measurement message, said controller determining the combined pilot signal strength of the pilot signals of the active legs identified in the pilot strength measurement message, comparing the combined pilot signal strength to a first threshold and providing a revised pilot strength measurement message which does not include the candidate pilot signals upon determination that the combined pilot signal strength is greater than the first threshold.
9. The base station of claim 8 , wherein said controller compares the pilot signal strength of a candidate pilot signal to a second threshold and provides a revised pilot strength measurement message which includes the candidate pilot signal upon determination that the pilot signal strength of the candidate pilot signal is greater than the second threshold.
10. The base station of claim 9 , wherein said controller compares the pilot signal strength of a candidate pilot signal to the pilot signal strength of a strongest pilot signal of the active legs and provides a revised pilot strength measurement message which includes the candidate pilot signal upon determination that the pilot signal strength of the candidate pilot signal is greater than the pilot signal strength of the strongest pilot signal of the active legs.
11. The base station of claim 8 , wherein said controller provides a revised pilot strength measurement message including the candidate pilot signals upon determination that the combined pilot signal strength is less than the first threshold.
12. The base station of claim 8 , further comprising a transmitter that transmits the revised pilot strength measurement message to a mobile switching center of the mobile communication system.
13. The base station of claim 8 , wherein the active legs of the mobile station are code division multiple access legs.
14. A mobile switching center of a mobile communication system, the mobile switching center receiving a pilot strength measurement message generated by a mobile station, the pilot strength measurement message identifying a pilot signal and pilot signal strength of at least one active leg of the mobile station and identifying at least one candidate pilot signal and pilot signal strength of the at least one candidate pilot signal, the mobile switching center comprising: a controller that revises the pilot strength measurement message, said controller determining the combined pilot signal strength of the pilot signals of the active legs identified in the pilot strength measurement message, comparing the combined pilot signal strength to a first threshold and providing a revised pilot strength measurement message which does not include the candidate pilot signals upon determination that the combined pilot signal strength is greater than the first threshold.
15. The mobile switching center of claim 14 , wherein said controller compares the pilot signal strength of a candidate pilot signal to a second threshold and provides a revised pilot strength measurement message including the candidate pilot signal upon determination that the pilot signal strength of the candidate pilot signal is greater than the second threshold.
16. The mobile switching center of claim 15 , wherein said controller compares the pilot signal strength of a candidate pilot signal to the pilot signal strength of a strongest pilot signal of the active legs and provides a revised pilot strength measurement message including the candidate pilot signal upon determination that the pilot signal strength of the candidate pilot signal is greater than the pilot signal strength of the strongest pilot signal of the active legs.
17. The mobile switching center of claim 14 , wherein said controller provides a revised pilot strength measurement message including the candidate pilot signals upon determination that the combined pilot signal strength is less than the first threshold.
18. The mobile switching center of claim 14 , wherein the pilot strength measurement message is provided from the mobile station to a base station, the mobile switching center further comprising: a receiver that receives the pilot strength measurement message transmitted from the base station.
19. The mobile switching center of claim 14 , wherein the active legs of the mobile station are code division multiple access legs.
20. A base station of a mobile communication system comprising: receiving means for receiving a pilot strength measurement message generated by a mobile station of the mobile communication system, the pilot strength measurement message identifying a pilot signal and pilot signal strength of at least one active leg of the mobile station and identifying at least one candidate pilot signal and pilot signal strength of the at least one candidate pilot signal; determination means for determining the combined pilot signal strength of the pilot signals of the active legs; comparison means, coupled to said determination means, for comparing the combined pilot signal strength of the pilot signals of the active legs to a first threshold; and modifying means, coupled to said comparison means, for providing a revised pilot strength measurement message which does not include the candidate pilot signals upon determination by said comparison means that the combined pilot signal strength is greater than the first threshold.
21. The base station of claim 20 , said comparison means also comparing the pilot signal strength of a candidate pilot signal to a second threshold, said modifying means providing a revised pilot strength measurement message as including the candidate pilot signal upon determination by said comparison means that the pilot signal strength of the candidate pilot signal is greater than the second threshold.
22. The base station of claim 21 , said comparison means also comparing the pilot signal strength of a candidate pilot signal to the pilot signal strength of a strongest pilot signal of the active legs, said modifying means providing a revised pilot strength measurement message as including the candidate pilot signal upon determination that the pilot signal strength of the candidate pilot signal is greater than the pilot signal strength of the strongest pilot of the active legs.
23. The base station of claim 20 , said modifying means providing a revised pilot strength measurement message as including the candidate pilot signals upon determination by said comparison means that the combined pilot signal strength is less than the first threshold.
24. The base station of claim 20 , wherein the active legs of the mobile station are code division multiple access legs.
25. The base station of claim 20 , further comprising transmitter means for transmitting the revised pilot strength measurement message to a mobile switching center of the mobile communication system.
26. An article of manufacture taking the form of a computer-readable medium for screening pilot signals of a pilot strength measurement message generated by a mobile station, the pilot strength measurement message identifying a pilot signal and pilot signal strength of at least one active leg of the mobile station and identifying at least one candidate pilot signal and pilot signal strength of the at least one candidate pilot signal, the article of manufacture comprising: a determination source code segment for causing a computer to determine the combined pilot signal strength of the pilot signals of the active legs; a first comparison source code segment for causing the computer to compare the combined pilot signal strength to a first threshold; and a first modifying source code segment for causing the computer to provide a revised pilot strength measurement message which does not include the candidate pilot signals when the combined pilot signal strength is greater than the first threshold.
27. The article of manufacture of claim 26 , further comprising: a second comparison source code segment for causing the computer to compare a candidate pilot signal to a second threshold; and a second modifying source code segment for causing the computer to provide a revised pilot strength measurement message as including the candidate pilot signal when the pilot signal strength of the candidate pilot signal is greater than the second threshold.
28. The article of manufacture of claim 27 , further comprising: a third comparison source code segment for causing the computer to compare the pilot signal strength of a candidate pilot signal to the pilot signal strength of a strongest pilot signal of the active legs; and a third modifying source code segment for causing the computer to provide a revised pilot strength measurement message including the candidate pilot signal when the pilot signal strength of the candidate pilot signal is greater than the pilot signal strength of the strongest pilot signal of the active legs.
29. The article of manufacture of claim 28 , further comprising: a fourth modifying source code segment for causing the computer to provide a revised pilot strength measurement message which does not include the candidate pilot signal when the pilot signal strength of the candidate pilot signal is not greater than the pilot signal strength of the strongest pilot signal of the active legs.
Cooperative Patent Classification codes for this invention. Click any code to explore related patents in that topic.
August 7, 1998
March 5, 2002
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